cocos2d-x の CREATE_FUNC を C++ っぽくしてみた

create_func.hpp

#ifndef CREATE_FUNC_HPP_INCLUDED
#define CREATE_FUNC_HPP_INCLUDED

/*
使い方:

class TestLayer : public cocos2d::Layer {
public:
  bool init();
  CREATE_FUNC(TestLayer);
};

と書く代わりに、以下のように書く。

class TestLayer : public cocos2d::Layer, create_func<TestLayer> {
public:
  bool init();
  using create_func::create;
};

CREATE_FUNC マクロと違い、引数はいくつでも大丈夫。

class TestLayer : public cocos2d::Layer, create_func<TestLayer> {
public:
  bool init(int a, std::string b);
  using create_func::create;
};

auto test = TestLayer::create(10, "abc");
*/
template<class Derived>
struct create_func {
    template<class... Args>
    static Derived* create(Args&&... args) {
        auto p = new Derived();
        if (p->init(std::forward<Args>(args)...)) {
            p->autorelease();
            return p;
        } else {
            delete p;
            return nullptr;
        }
    }
};

#endif // CREATE_FUNC_HPP_INCLUDED